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<a class="jxr_linenumber" name="1" href="#1">1</a>   <strong class="jxr_keyword">package</strong> de.aikiit.bildbearbeiter.image;
<a class="jxr_linenumber" name="2" href="#2">2</a>   
<a class="jxr_linenumber" name="3" href="#3">3</a>   <strong class="jxr_keyword">import</strong> org.apache.log4j.Logger;
<a class="jxr_linenumber" name="4" href="#4">4</a>   <strong class="jxr_keyword">import</strong> org.apache.sanselan.ImageReadException;
<a class="jxr_linenumber" name="5" href="#5">5</a>   <strong class="jxr_keyword">import</strong> org.apache.sanselan.Sanselan;
<a class="jxr_linenumber" name="6" href="#6">6</a>   <strong class="jxr_keyword">import</strong> org.apache.sanselan.common.IImageMetadata;
<a class="jxr_linenumber" name="7" href="#7">7</a>   <strong class="jxr_keyword">import</strong> org.apache.sanselan.formats.jpeg.JpegImageMetadata;
<a class="jxr_linenumber" name="8" href="#8">8</a>   <strong class="jxr_keyword">import</strong> org.apache.sanselan.formats.tiff.TiffField;
<a class="jxr_linenumber" name="9" href="#9">9</a>   <strong class="jxr_keyword">import</strong> org.apache.sanselan.formats.tiff.constants.TagInfo;
<a class="jxr_linenumber" name="10" href="#10">10</a>  <strong class="jxr_keyword">import</strong> org.apache.sanselan.formats.tiff.constants.TiffConstants;
<a class="jxr_linenumber" name="11" href="#11">11</a>  
<a class="jxr_linenumber" name="12" href="#12">12</a>  <strong class="jxr_keyword">import</strong> java.io.File;
<a class="jxr_linenumber" name="13" href="#13">13</a>  <strong class="jxr_keyword">import</strong> java.io.IOException;
<a class="jxr_linenumber" name="14" href="#14">14</a>  <strong class="jxr_keyword">import</strong> java.text.ParseException;
<a class="jxr_linenumber" name="15" href="#15">15</a>  
<a class="jxr_linenumber" name="16" href="#16">16</a>  <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="17" href="#17">17</a>  <em class="jxr_javadoccomment"> * Helper class to extract metadata from given images. This class uses Apache</em>
<a class="jxr_linenumber" name="18" href="#18">18</a>  <em class="jxr_javadoccomment"> * Sanslean to perform the metadata extraction itself.</em>
<a class="jxr_linenumber" name="19" href="#19">19</a>  <em class="jxr_javadoccomment"> */</em>
<a class="jxr_linenumber" name="20" href="#20">20</a>  <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">class</strong> <a href="../../../../de/aikiit/bildbearbeiter/image/MetaDataExtractor.html">MetaDataExtractor</a> {
<a class="jxr_linenumber" name="21" href="#21">21</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="22" href="#22">22</a>  <em class="jxr_javadoccomment">     * This class' logger.</em>
<a class="jxr_linenumber" name="23" href="#23">23</a>  <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="24" href="#24">24</a>      <strong class="jxr_keyword">private</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> Logger LOG = Logger.getLogger(MetaDataExtractor.<strong class="jxr_keyword">class</strong>);
<a class="jxr_linenumber" name="25" href="#25">25</a>  
<a class="jxr_linenumber" name="26" href="#26">26</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="27" href="#27">27</a>  <em class="jxr_javadoccomment">     * Constant for an empty string.</em>
<a class="jxr_linenumber" name="28" href="#28">28</a>  <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="29" href="#29">29</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String EMPTY_STRING = <span class="jxr_string">""</span>;
<a class="jxr_linenumber" name="30" href="#30">30</a>  
<a class="jxr_linenumber" name="31" href="#31">31</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="32" href="#32">32</a>  <em class="jxr_javadoccomment">     * Constant for a blank character.</em>
<a class="jxr_linenumber" name="33" href="#33">33</a>  <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="34" href="#34">34</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String SPACE = <span class="jxr_string">" "</span>;
<a class="jxr_linenumber" name="35" href="#35">35</a>  
<a class="jxr_linenumber" name="36" href="#36">36</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="37" href="#37">37</a>  <em class="jxr_javadoccomment">     * Constant for an underscor character.</em>
<a class="jxr_linenumber" name="38" href="#38">38</a>  <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="39" href="#39">39</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String UNDERSCORE = <span class="jxr_string">"_"</span>;
<a class="jxr_linenumber" name="40" href="#40">40</a>  
<a class="jxr_linenumber" name="41" href="#41">41</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="42" href="#42">42</a>  <em class="jxr_javadoccomment">     * Constant for a colon.</em>
<a class="jxr_linenumber" name="43" href="#43">43</a>  <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="44" href="#44">44</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String COLON = <span class="jxr_string">":"</span>;
<a class="jxr_linenumber" name="45" href="#45">45</a>  
<a class="jxr_linenumber" name="46" href="#46">46</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="47" href="#47">47</a>  <em class="jxr_javadoccomment">     * Constant for an apostrophe.</em>
<a class="jxr_linenumber" name="48" href="#48">48</a>  <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="49" href="#49">49</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> String APOSTROPHE = <span class="jxr_string">"'"</span>;
<a class="jxr_linenumber" name="50" href="#50">50</a>  
<a class="jxr_linenumber" name="51" href="#51">51</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="52" href="#52">52</a>  <em class="jxr_javadoccomment">     * Constant to describe a valid length of an EXIF date (currently 21).</em>
<a class="jxr_linenumber" name="53" href="#53">53</a>  <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="54" href="#54">54</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> <strong class="jxr_keyword">final</strong> <strong class="jxr_keyword">int</strong> VALID_EXIF_DATE_LENGTH = 21;
<a class="jxr_linenumber" name="55" href="#55">55</a>  
<a class="jxr_linenumber" name="56" href="#56">56</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="57" href="#57">57</a>  <em class="jxr_javadoccomment">     * Constructor is not visible to avoid instantiation.</em>
<a class="jxr_linenumber" name="58" href="#58">58</a>  <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="59" href="#59">59</a>      <strong class="jxr_keyword">private</strong> <a href="../../../../de/aikiit/bildbearbeiter/image/MetaDataExtractor.html">MetaDataExtractor</a>() {
<a class="jxr_linenumber" name="60" href="#60">60</a>          <em class="jxr_comment">// prevent instantiation of this utility class</em>
<a class="jxr_linenumber" name="61" href="#61">61</a>      }
<a class="jxr_linenumber" name="62" href="#62">62</a>  
<a class="jxr_linenumber" name="63" href="#63">63</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="64" href="#64">64</a>  <em class="jxr_javadoccomment">     * Returns the requested tag as String from the image file.</em>
<a class="jxr_linenumber" name="65" href="#65">65</a>  <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="66" href="#66">66</a>  <em class="jxr_javadoccomment">     * @param image Image file to extract Metadata from.</em>
<a class="jxr_linenumber" name="67" href="#67">67</a>  <em class="jxr_javadoccomment">     * @param tag   Tag to extract from the given file, @see TiffConstants</em>
<a class="jxr_linenumber" name="68" href="#68">68</a>  <em class="jxr_javadoccomment">     * @return Returns exif tag value, in case of any errors the value is an</em>
<a class="jxr_linenumber" name="69" href="#69">69</a>  <em class="jxr_javadoccomment">     *         empty String.</em>
<a class="jxr_linenumber" name="70" href="#70">70</a>  <em class="jxr_javadoccomment">     * @throws IOException        if file cannot be accessed.</em>
<a class="jxr_linenumber" name="71" href="#71">71</a>  <em class="jxr_javadoccomment">     * @throws ImageReadException if an error occurred during image processing.</em>
<a class="jxr_linenumber" name="72" href="#72">72</a>  <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="73" href="#73">73</a>      <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> String getExifMetadata(<strong class="jxr_keyword">final</strong> File image,
<a class="jxr_linenumber" name="74" href="#74">74</a>                                           <strong class="jxr_keyword">final</strong> TagInfo tag)
<a class="jxr_linenumber" name="75" href="#75">75</a>              <strong class="jxr_keyword">throws</strong> IOException, ImageReadException {
<a class="jxr_linenumber" name="76" href="#76">76</a>          assert image != <strong class="jxr_keyword">null</strong> : <span class="jxr_string">"Parameter image must not be null"</span>;
<a class="jxr_linenumber" name="77" href="#77">77</a>          assert tag != <strong class="jxr_keyword">null</strong> : <span class="jxr_string">"Parameter tag must not be null"</span>;
<a class="jxr_linenumber" name="78" href="#78">78</a>  
<a class="jxr_linenumber" name="79" href="#79">79</a>          String result = EMPTY_STRING;
<a class="jxr_linenumber" name="80" href="#80">80</a>          IImageMetadata metadata = Sanselan.getMetadata(image);
<a class="jxr_linenumber" name="81" href="#81">81</a>          <strong class="jxr_keyword">if</strong> (metadata instanceof JpegImageMetadata) {
<a class="jxr_linenumber" name="82" href="#82">82</a>              JpegImageMetadata jpegMetadata = (JpegImageMetadata) metadata;
<a class="jxr_linenumber" name="83" href="#83">83</a>              TiffField field = jpegMetadata.findEXIFValue(tag);
<a class="jxr_linenumber" name="84" href="#84">84</a>              <strong class="jxr_keyword">if</strong> (field != <strong class="jxr_keyword">null</strong>) {
<a class="jxr_linenumber" name="85" href="#85">85</a>                  result = field.getValueDescription();
<a class="jxr_linenumber" name="86" href="#86">86</a>                  LOG.info(<span class="jxr_string">"extraction of "</span> + tag.getDescription()
<a class="jxr_linenumber" name="87" href="#87">87</a>                          + <span class="jxr_string">" yields "</span> + result);
<a class="jxr_linenumber" name="88" href="#88">88</a>              }
<a class="jxr_linenumber" name="89" href="#89">89</a>          }
<a class="jxr_linenumber" name="90" href="#90">90</a>          <strong class="jxr_keyword">return</strong> (result == <strong class="jxr_keyword">null</strong> ? EMPTY_STRING : result);
<a class="jxr_linenumber" name="91" href="#91">91</a>      }
<a class="jxr_linenumber" name="92" href="#92">92</a>  
<a class="jxr_linenumber" name="93" href="#93">93</a>      <em class="jxr_javadoccomment">/**</em>
<a class="jxr_linenumber" name="94" href="#94">94</a>  <em class="jxr_javadoccomment">     * Helper to extract the date this image was created to be used during the</em>
<a class="jxr_linenumber" name="95" href="#95">95</a>  <em class="jxr_javadoccomment">     * renaming process.</em>
<a class="jxr_linenumber" name="96" href="#96">96</a>  <em class="jxr_javadoccomment">     * &lt;p/&gt;</em>
<a class="jxr_linenumber" name="97" href="#97">97</a>  <em class="jxr_javadoccomment">     * In the EXIF standard itself the following convention for dates as is</em>
<a class="jxr_linenumber" name="98" href="#98">98</a>  <em class="jxr_javadoccomment">     * defined: &lt;i&gt; D. Other Tags DateTime The date and time of image creation.</em>
<a class="jxr_linenumber" name="99" href="#99">99</a>  <em class="jxr_javadoccomment">     * In this standard it is the date and time the file was changed. The format</em>
<a class="jxr_linenumber" name="100" href="#100">100</a> <em class="jxr_javadoccomment">     * is "YYYY:MM:DD HH:MM:SS" with time shown in 24-hour format, and the date</em>
<a class="jxr_linenumber" name="101" href="#101">101</a> <em class="jxr_javadoccomment">     * and time separated by one blank character [20.H]. When the date and time</em>
<a class="jxr_linenumber" name="102" href="#102">102</a> <em class="jxr_javadoccomment">     * are unknown, all the character spaces except colons (":") may be filled</em>
<a class="jxr_linenumber" name="103" href="#103">103</a> <em class="jxr_javadoccomment">     * with blank characters, or else the Interoperability field may be filled</em>
<a class="jxr_linenumber" name="104" href="#104">104</a> <em class="jxr_javadoccomment">     * with blank characters. The character string length is 20 bytes including</em>
<a class="jxr_linenumber" name="105" href="#105">105</a> <em class="jxr_javadoccomment">     * NULL for termination. When the field is left blank, it is treated as</em>
<a class="jxr_linenumber" name="106" href="#106">106</a> <em class="jxr_javadoccomment">     * unknown. Tag = 306 (132.H) Type = ASCII Count = 20 Default = none &lt;/i&gt;</em>
<a class="jxr_linenumber" name="107" href="#107">107</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="108" href="#108">108</a> <em class="jxr_javadoccomment">     * If the extracted date value is empty - no new file name is generated.</em>
<a class="jxr_linenumber" name="109" href="#109">109</a> <em class="jxr_javadoccomment">     *</em>
<a class="jxr_linenumber" name="110" href="#110">110</a> <em class="jxr_javadoccomment">     * @param image Image to extract metadata from.</em>
<a class="jxr_linenumber" name="111" href="#111">111</a> <em class="jxr_javadoccomment">     * @return the date this image was created if found, format is</em>
<a class="jxr_linenumber" name="112" href="#112">112</a> <em class="jxr_javadoccomment">     * @throws ParseException     If metadata cannot be parsed correctly.</em>
<a class="jxr_linenumber" name="113" href="#113">113</a> <em class="jxr_javadoccomment">     * @throws ImageReadException If image cannot be read.</em>
<a class="jxr_linenumber" name="114" href="#114">114</a> <em class="jxr_javadoccomment">     * @throws IOException        If an error occurs when accessing the image's</em>
<a class="jxr_linenumber" name="115" href="#115">115</a> <em class="jxr_javadoccomment">     *                            metadata.</em>
<a class="jxr_linenumber" name="116" href="#116">116</a> <em class="jxr_javadoccomment">     * @see &lt;a href="<a href="http://www.exif.org/samples/canon-ixus.html" target="alexandria_uri">http://www.exif.org/samples/canon-ixus.html</a>"&gt;Canon EXIF</em>
<a class="jxr_linenumber" name="117" href="#117">117</a> <em class="jxr_javadoccomment">     *      example page&lt;/a&gt;</em>
<a class="jxr_linenumber" name="118" href="#118">118</a> <em class="jxr_javadoccomment">     * @see &lt;a href="<a href="http://www.exif.org/specifications.html" target="alexandria_uri">http://www.exif.org/specifications.html</a>"&gt;EXIF</em>
<a class="jxr_linenumber" name="119" href="#119">119</a> <em class="jxr_javadoccomment">     *      specifications&lt;/a&gt;</em>
<a class="jxr_linenumber" name="120" href="#120">120</a> <em class="jxr_javadoccomment">     * @see &lt;a href="<a href="http://www.exif.org/Exif2-2.PDF" target="alexandria_uri">http://www.exif.org/Exif2-2.PDF</a>"&gt;EXIF2-2.pdf</em>
<a class="jxr_linenumber" name="121" href="#121">121</a> <em class="jxr_javadoccomment">     *      specification&lt;/a&gt;</em>
<a class="jxr_linenumber" name="122" href="#122">122</a> <em class="jxr_javadoccomment">     */</em>
<a class="jxr_linenumber" name="123" href="#123">123</a> 
<a class="jxr_linenumber" name="124" href="#124">124</a>     <strong class="jxr_keyword">public</strong> <strong class="jxr_keyword">static</strong> String generateCreationDateInCorrectFormat(<strong class="jxr_keyword">final</strong> File image)
<a class="jxr_linenumber" name="125" href="#125">125</a>             <strong class="jxr_keyword">throws</strong> ImageReadException, IOException, ParseException {
<a class="jxr_linenumber" name="126" href="#126">126</a>         String dateValue =
<a class="jxr_linenumber" name="127" href="#127">127</a>                 getExifMetadata(image, TiffConstants.EXIF_TAG_CREATE_DATE);
<a class="jxr_linenumber" name="128" href="#128">128</a> 
<a class="jxr_linenumber" name="129" href="#129">129</a>         LOG.info(<span class="jxr_string">"EXIF date value is: "</span> + dateValue);
<a class="jxr_linenumber" name="130" href="#130">130</a>         <strong class="jxr_keyword">if</strong> (dateValue != <strong class="jxr_keyword">null</strong> &amp;&amp; dateValue.length() &gt; 0) {
<a class="jxr_linenumber" name="131" href="#131">131</a> 
<a class="jxr_linenumber" name="132" href="#132">132</a>             assert dateValue.length() == VALID_EXIF_DATE_LENGTH
<a class="jxr_linenumber" name="133" href="#133">133</a>                     : <span class="jxr_string">"Invalid length of EXIF metadata, "</span>
<a class="jxr_linenumber" name="134" href="#134">134</a>                     + <span class="jxr_string">"not complying to the standard."</span>;
<a class="jxr_linenumber" name="135" href="#135">135</a> 
<a class="jxr_linenumber" name="136" href="#136">136</a>             <em class="jxr_comment">// Date parsing with apache.DateUtils or JDK-DateFormats</em>
<a class="jxr_linenumber" name="137" href="#137">137</a>             <em class="jxr_comment">// does not work due to '-signs in the date string</em>
<a class="jxr_linenumber" name="138" href="#138">138</a>             <em class="jxr_comment">// (unparseable pattern is "'yyyy:MM:dd HH:mm:ss'")</em>
<a class="jxr_linenumber" name="139" href="#139">139</a> 
<a class="jxr_linenumber" name="140" href="#140">140</a>             <em class="jxr_comment">// replace special characters to extract digits only</em>
<a class="jxr_linenumber" name="141" href="#141">141</a>             dateValue = dateValue.replaceAll(APOSTROPHE, EMPTY_STRING);
<a class="jxr_linenumber" name="142" href="#142">142</a>             dateValue = dateValue.replaceAll(COLON, EMPTY_STRING);
<a class="jxr_linenumber" name="143" href="#143">143</a>             dateValue = dateValue.replaceAll(SPACE, UNDERSCORE);
<a class="jxr_linenumber" name="144" href="#144">144</a>             dateValue += UNDERSCORE;
<a class="jxr_linenumber" name="145" href="#145">145</a>             <em class="jxr_comment">//convert '2011:01:30 13:11:02' to "yyyyMMdd_HHmm_"+fileName</em>
<a class="jxr_linenumber" name="146" href="#146">146</a>             dateValue += image.getName();
<a class="jxr_linenumber" name="147" href="#147">147</a> 
<a class="jxr_linenumber" name="148" href="#148">148</a>             LOG.info(<span class="jxr_string">"Target filename is: "</span> + dateValue);
<a class="jxr_linenumber" name="149" href="#149">149</a>             <strong class="jxr_keyword">return</strong> dateValue;
<a class="jxr_linenumber" name="150" href="#150">150</a>         }
<a class="jxr_linenumber" name="151" href="#151">151</a>         LOG.info(<span class="jxr_string">"No creation date extracted from file "</span> + image);
<a class="jxr_linenumber" name="152" href="#152">152</a> 
<a class="jxr_linenumber" name="153" href="#153">153</a>         <strong class="jxr_keyword">return</strong> EMPTY_STRING;
<a class="jxr_linenumber" name="154" href="#154">154</a>     }
<a class="jxr_linenumber" name="155" href="#155">155</a> }
</pre>
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